Insomuch that most of the common temperature-rated D.C. electric fans that exist in the marketplace have largely been fitted with integrated circuit components as the temperature control circuit, and some of the widely used temperature-control components are none other tan model LB 1860, 8473 and the like, which are of pulse-rated fabrication technique that not only do not offer a dependable temperature control effect but can produce excessive electromagnetic noise at low cycles, not to mention that such condense circuit components are expensive in cost, not readily available for purchase to lead to a cost hike and an extended production cycle. In addition, there is also a type of temperature-rated electric fan out on the market that incorporates a thermal-resistor structure at the current source, if not for the fact that such circuit thermal-resistor consumes excessive power and can be tricky in temperature control due to unpredictable temperature curves.
Through which, issues that relate addressing some of the shortcomings of the foregoing common temperature-rated D.C. electric fan, such as a less than dependable temperature control function, excessive electromagnetic noise at low cycles, costly component price in fabrication, source of goods at purchasing, availability in purchasing, which only lead to cost increase and extended production cycle, have presented themselves as a compelling area for the industry to look into improvement and R&D in terms of devising an innovative fan-specific temperature-rated variable speed control circuit that truly works.